Low Tech Ferrocement Roof Building System

Low tech ferrocement roof in the Philippines
Low tech ferrocement roof in the Philippines

“Total roof size 360sqm approx
1 inch wire mesh 22 gauge
Days worked so far: 34 working days till last layer on last section laid.
Total cost so far $2800 not including patio post rebuild. Also waterproofing and painting not included but whole roof is covered.

We removed all straw FIRST before putting a tarp backing on existing bamboo frame. We worked slowly up without removing all the straw on roof as we are living here while we build. Wire mesh is embedded in cement. Since we had no wood backing, just tarp, we put a first layer of 2 wire mesh and half inch of cement. Once hard next day we put 2nd layer or 3 wire mesh and final layer. Total 5 layers mesh. Once past the wall bond beam going up we cut down to 4 layers mesh. On last section next to metal compression ring on top, our sand deliverer misdelivered fine sand instead of coarse. Our workers didnt know and so next day our first layer had BIG cracks. We fixed this by using leftover batch of coarse sand and covered it up along w 1 layer mesh. Then we put in a final layer. So our last section up top has 3 layers of cement and mesh. Hope this mistake helps anyone else.

Another fixup is that mason put one of our pvc pipe vents off slope and it was tilted very slightly up. I found mistake after cement hardened. I just blocked the vent with a plastic bag. Will fix in future with a elbow joint pointing down. Rite now i don’t need it as i have 11 other vents up top.

Finally Holcim cement or any other brand in philippines is SUBSTANDARD. Our workaround is to make our layers thicker. Total roof thickness is still a thin 2 inch or 3 by patio and bond beam.

Thats it. As of now we are putting rebar and wire mesh on patio posts. Then cement. It’s to hold up patio long term.”

Ang Aming Bahay Nalupa blog
Note: The most important step is the mesh must be completely embedded in cement. It won’t work if you just put cement on one side of the mesh.

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